Left ventricular inflow propagation velocity: comparisons between pulsed wave and color M-mode Doppler echocardiography

Determination of Pulmonary Capillary Wedge Pressure Using Pulsed Wave Doppler Echocardiography: Clinical Application of Range Ambiguity Phenomenon

To predict pulmonary capillary wedge pressure (PCWP) noninvasively, several Doppler combination indices have been developed. Recently, a fair correlation has been found between the time constant of isovolumic left ventricular (LV) relaxation (tau) and pulsed wave Doppler LV inflow propagation velocity (LVIPVpw) derived through the application of range ambiguity phenomenon. In the measurement of LVIPVpw, we can simultaneously measure the peak phantom E-wave velocity (Ep) from the same heartbeat. Hence, it is hypothesized that Ep/LVIPVpw is a useful index in predicting PCWP. In all, 29 patients who underwent elective cardiac catheterization for suggested coronary artery disease were included. Mean PCWP (mPCWP) obtained from right heart catheterization was compared with echocardiographic data before and 5 minutes after sublingual application of nitroglycerin (0.6 mg). Nitroglycerin caused a significant decrease in Ep and mPCWP, but not in LVIPVpw (P < .001, P < .001, and P = .687, respectively). By stepwise multiple linear regression analysis, only the Ep/LVIPVpw (beta = 0.832, P < .001) was the independent predictor of mPCWP. After nitroglycerin intake, the change in mPCWP was significantly correlated with the change in Ep/LVIPVpw (r = 0.455, P = .015). The sensitivity and specificity of Ep/LVIPVpw > 0.74 in predicting mPCWP > 15 mm Hg were 78% and 90%, respectively (area under curve 0.86). In conclusion, Ep/LVIPVpw derived from the same heartbeat provides a good estimate of mPCWP and can be used to rapidly track the change in mPCWP.

Left ventricular inflow propagation velocity at pulsed wave Doppler analysis: An index of relaxation

To test whether left ventricular inflow propagation velocity at the pulsed wave Doppler analysis (IPVpw) is a useful noninvasive index of relaxation, 21 patients under coronary angiography for chest pain were included for simultaneous catheter-based and Doppler studies. IPVpw was derived through the application of range ambiguity, and the time constant of isovolumic left ventricular pressure decline (tau) was acquired by a previously described method. At baseline status, IPVpw correlated significantly with the peak negative dP/dt and tau ( r = -0.609, P = .003), but not with the peak velocity of transmitral early flow (E) wave. Sublingual application of nitroglycerin increased heart rate, decreased the transmitral E velocity and transmitral E-to-A velocity ratio, and prolonged the deceleration time of the transmitral E wave. However, there was no significant impact on IPVpw, peak negative dP/dt, or tau. IPVpw correlated with tau ( r = -0.533, P < .001) at the combined analysis of the data before and after nitroglycerin application. In conclusion, IPVpw is a preload-independent, noninvasive index of left ventricular relaxation.